Description: Livestock manure, as recyclable sources for nitrogen (N) and phosphorus (P) in the Soil-Plant-Animal system, plays an important role in nutrient cycling. Given the agricultural benefits and environmental pollutions brought by manure, it is of great importance to estimate the spatial variations and temporal trajectories of manure production and its application in croplands of the continental United States (U.S.). Here, we developed datasets of annual animal manure N and P production and application in the continental U.S. at a 30 arc-second resolution over the period of 1860-2017. The total production of manure N and P increased from 1.4 Tg N yr-1 and 0.3 Tg P yr-1 in 1860 to 7.4 Tg N yr-1 and 2.3 Tg P yr-1 in 2017. The increasing manure nutrient production was associated with increased livestock numbers before the 1980s and enhanced livestock weights after the 1980s. The high-nutrient region mainly enlarged from the Midwest toward the Southern U.S., and became more concentrated in numerous hot spots after the 1980s. The South Atlantic-Gulf and Mid-Atlantic basins were the two critical coastal regions with high environmental risks due to the enrichment of manure nutrient production and application from the 1970s to 2010s. Our long-term manure N and P datasets provide critical information for national and regional assessments of nutrient budgets and can also serve as the input data for ecosystem and hydrological models to examine biogeochemical cycles in terrestrial and aquatic ecosystems.

Description: Production and application to soils of manure excreta from livestock production significantly perturb the global nutrient balance and result in significant greenhouse gas emissions that warm the earth's climate. Despite much attention paid to synthetic nitrogen (N) fertilizer and manure N applications to croplands, spatially-explicit, continuous time-series datasets of manure and fertilizer N inputs on pastures and rangelands are lacking. We developed three global gridded datasets at a resolution of 0.5 degree by 0.5 degree for the period 1860-2016 (i.e., annual manure N deposition (by grazing animals) rate, synthetic N fertilizer and N manure application rates), by combining annual and 5-arc minute spatial data on pastures and rangelands with country-level statistics on livestock manure, mineral and chemical fertilizers, and land use information for cropland and permanent meadows and pastures from the Food and Agricultural Organization database (FAOSTAT). Based on the new data products, we estimated that total N inputs, sum of manure N deposition, manure and fertilizer N application to pastures and rangelands increased globally from 15 to 101 Tg N yr-1 during 1860-2016. In particular during the period 2000-2016, livestock manure N deposition accounted for 83% of the total N inputs, whereas manure and fertilizer N application accounted 9% and 8%, respectively. At the regional scale, hotspots of manure N deposition remained largely similar during the period 1860-2016 (i.e., southern Asia, Africa, and South America), however hotspots of manure and fertilizer N application shifted from Europe to southern Asia in the early 21st century. The new three global datasets contribute to fill previous data gaps of global and regional N inputs in pastures and rangelands, improving the ability of ecosystem and biogeochemistry models to investigate the global impacts of N enrichment due to agriculture, in terms of associated greenhouse gas emissions and environmental sustainability issues.

Description: Excessive anthropogenic nitrogen (N) inputs to the biosphere have disrupted the global nitrogen cycle. To better quantify the spatial and temporal patterns of anthropogenic N enrichments, assess their impacts on the biogeochemical cycles of the planet and other living organisms, and improve nitrogen use efficiency (NUE) for sustainable development, we develop a comprehensive and synthetic dataset for anthropogenic N inputs to the terrestrial biosphere. This Harmonized Anthropogenic N Inputs (HaNi) dataset takes advantage of different data sources in a spatiotemporally consistent way to generate a set of high-resolution gridded N input products from the preindustrial to present (1860-2019). The HaNi dataset includes annual rates of synthetic N fertilizer, manure application/deposition, and atmospheric N deposition in cropland, pasture, and rangeland at 5-arcmin. Specifically, the N inputs are categorized, according to the N forms and the land use, as 1) NH4-N fertilizer applied to cropland, 2) NO3-N fertilizer applied to cropland, 3) NH4-N fertilizer applied to pasture, 4) NO3-N fertilizer applied to pasture, 5) manure N application on cropland, 6) manure N application on pasture, 7) manure N deposition on pasture, 8) manure N deposition on rangeland, 9) NHx-N deposition, and 10) NOy-N deposition. The total anthropogenic N (TN) inputs to global terrestrial ecosystems increased from 29.05 Tg N yr-1 in the 1860s to 267.23 Tg N yr-1 in the 2010s, with the dominant N source changing from atmospheric N deposition (before the 1900s) to manure N (the 1910s-2000s), and to synthetic fertilizer in the 2010s. The proportion of synthetic NH4-N fertilizer increased from 64% in the 1960s to 90% in the 2010s, while synthetic NO3-N fertilizer decreased from 36% in the 1960s to 10% in the 2010s. Hotspots of TN inputs shifted from Europe and North America to East and South Asia during the 1960s-2010s. Such spatial and temporal dynamics captured by the HaNi dataset are expected to facilitate a comprehensive assessment of the coupled human-earth system and address a variety of social welfare issues, such as climate-biosphere feedback, air pollution, water quality, and biodiversity.